Centrifugal blasting apparatus



Feb. 13, 1968 w. J. PHYSIOC m 3,368,308

CENTRIFUGAL BLASTING APPARATUS Filed Nov. 3, 1964 2 Sheets-Sheet 1INVENTOR ATTORNEYS M1113 \fPl ysiocfl 3 Feb. 13, 1968 w. J. PHYSIOC m3,368,308

CENTR IFUGAL BLASTING APPARATUS Filed Nov. 1 1964 2 Sheets-Sheet 2IN-VENTOR Willis JP@OC,H

ATTORNEYS 3,368,308 CENTRIFUGAL BLASTING APPARATUS Willis J. PhysiocIII, Boonsboro, Md., assignor to The Pangborn Corporation, Hagerstown,Md., a corporation of Delaware Filed Nov. 3, 1964, Ser. No. 408,590 6Claims. (Cl. 51-9) This invention relates to a centrifugal blastingapparatus. More particularly to such an apparatus as that shown in US.Patent No. 2,582,702, granted Ian. 15, 1952, and US. Patent No.2,869,289, granted Jan. 20, 1959, which apparatus projects a directionalstream of blastant particles.

Among the objects of the present invention is the provision of novelcentrifugal blasting apparatus for use in substantially any orientationto provide the ability to remotely control the range of blastingpattern, heretofore, not done.

Further objects of the present invention include a novel means forangularly adjusting and controlling the size of the feed slot of theimpeller cage.

The above, as well as still further objects of the present inventionwill be more clearly understood from the following description anddrawings wherein:

FIG. 1 is a side view of one embodiment of the invention in one phase ofoperation;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a section taken along line 33 of FIG. 2;

FIG. 4 is a view similar to FIG. 1 showing another phase of operation;

FIG. Sis a section similar to FIG. 2 of operation of FIG. 4;

FIG. 6 is a section of another embodiment of this invention; and

FIG. 7 is a section taken along line 77 of FIG. 6.

According to the present invention a centrifugal throwing wheel assemblyincludes a throwing wheel carried on one end of a rotatable shaft forrotation to project tangentially particles fed to the central portion ofthe wheel from an impeller cage. The impeller cage directs the abrasiveparticles through its feed slot against the rotating vanes positionedradially along the periphery of the wheel. The abrasive blast pattern isshifted in a longitudinal manner through a remote controlling of anadjustable actuating mechanism which is connected to the impeller cageto regulate the orientation of the impeller cage feed slot with respectto the work piece. Advantageously, the cage retaining fasteners whichmount the impeller cage to the throwing wheel housing are spring loadedto assure that the rotating joint between the cage and housing issealed. e

The remote actuating mechanism includes a small drive unit or ahydraulic cylinder-piston assembly connected to the impeller cage tomove its feed slot along an arc. The movement of the feed slot may alsobe controlled by means of a servo-unit and by manually adjustable stopsand can be set in a predetermined manner such that the cage and its feedslot are oscillated at a preset frequency or, if desired, the remotecontrol mechanism can be set to position the feed-slot at apredetermined angle with respect to the workpiece to accurately controldisposition of the blast pattern from the feed slot.

In accordance with another aspect of this invention, the size of thefeed slot of the impeller cage is also remotely controlled as follows:The impeller cage is formed of a pair of concentric cylindrical rings,each with a slot. One of the rings is relatively stationary and theother is rotatable by means of a remote control actuating mechanism.When the slots of both rings are aligned, the efshowing a phase fectivesize of the feed slot is at a maximum and is gradually reduced as theslots move out of alignment.

Referring to the drawings, the apparatus in FIG. 2 includes a throwingwheel 20 and a shaft 30 rotatably mounted on suitable journals andcarrying a runner head 32 upon which throwing blades or vanes 34 aremounted. The shaft 30 is provided at one end with an enlarged flange 36to which head 32 can be firmly secured as by means of bolts penetratingthrough the flange and runner head from either side. The runner head isdesirably of massive construction so that unsymmetric errosion of thethrowing blades will not significantly unbalance the unit dynamically.

The blades or vanes 34 are equally spaced around the runner head 32 asshown in FIG. 3 and can be held in any suitable manner such as by use ofan enlarged dovetailed edge on one side of the vane snugly engaging witha corresponding dove-tailed slot 39 in the face of the runner head 32.At their central ends the vanes are spaced apart to leave room for afeed assembly. Each blade is shown as held in place by a pin 38 (FIG. 2)which is fitted into suitable aligned sockets in both the enlargeddove-tailed edge of vane 34 and the face of the runner head 32. In theopenings provided at the center of the runner head there is positioned adischarge directing feed cage 40 which is generally cylindrical orcup-shaped in form having an outwardly marginal flange 42 which issuitably secured to an external housing 44. The housing in turn isanchored to a frame 46 as shown in FIG. 2 that forms part of thejournals for shaft 30 and serves to securely hold the assembled partstogether.

The bottom 48 of the cup-shaped cage 40 has a central aperture 50 andits side is provided with a feed slot 52. Within the cage there ismounted an impeller 54 that includes a plurality of vanes 56 carrying atone end, a cylindrical boss 58 which fits through cage opening 50 and bymeans of which it is fastened to the runner head. A central bolt 60, asshown in FIG. 2, serves as a threaded fastener. The interior of theimpeller 54 is hollow and is supplied with blastant particles as bymeans of the spout 62 which can be fastened to the housing and whichextends well into the cage 40 and close to the front opening of theimpeller. A wear plate structure 61 is mounted internally of housing 44.Feed cage 40 is rotatably secured to housing 44 as will later bedescribed in detail. Cage retaining fasteners 64 (shown in FIG. 1) whichsecure cage 40 to housing 44 are spring loaded to effectively seal therotating joint. Additionally, the point is lubricated with, for example,molydisulfide (Mos to prevent galling of the rotating members.

The cage also carries a mark which cooperates with scale 77 that issecured to housing 44 as shown in FIG. 1 and FIG. 4. The position ofmark 75 on scale 77 from a distance indicates the relative position offeed slot 52, as will later be described.

As also shown in FIGS. 1 and 4, a lever arm 80 is connected to cage 40.Arm 80 is pivo tably mounted to one end of piston rod 82 with anextension 84 of arm 80 projecting above the clevis 86. The opposite endof piston rod 82 reciprocates in hydraulic cylinder 8-8. This reciprocalmotion is remotely controlled by servo motor through pump92 which has apair of lines 93 and 94 leading to each end of cylinder 88. p I

A pair of adjustable stops 96 and 98 are mounted on rod 100 under pistonrod 82. Stops 96 and 98 cooperate with projection 102 on piston rod 82to define or limit the amplitude of the stroke of piston 82. The strokemay accordingly be controlled by manually adjusting the relativeposition of stops 96 and 98 on rod 100.

FIG. 1 shows the blast pattern 104 against workpiece 106 in anintermediate position of piston rod 82 when 3 projection 102 is betweenstops 96 and 98. This blast pattern results from the position of feedslot 52 as shown in FIG. 3. The position of slot 52 can easily be seenor indicated by marker 75 and scale 77.

When it is desired, for example, to move blast pattern 104 more to theright on workpiece 106, the operator actuates servo-unit 90 to retractor shift piston rod 82 to the left. FIG. 4 shows piston rod 82 moved tothe left in its most extreme position with the projection 102 againststop 96. An elastic electrical resistor unit 108, secured to extension84 on piston rod 82 and to post 110 on hydraulic cylinder 88, is used tosense, through changes in resistance, the position of the cage. Thesechanges in resistance, due to changes in length, are used to showgraphically on gauge 109, the angular positions of cage 40 and slot 52.This occurs because resistor 108 changes voltage in the electricalcircuit 113, thereby changing the position of an armature in smallgalvanometer type gauge 109 which is calibrated to indicate the changein angular orientation of cage 40.

As piston rod 82 is moved to the position shown in FIG. 4, cage 40 isrotated counter-clockwise by arm 80 and accordingly feed slot 52 isrotated in an arc to the position shown in FIG. 5. When feed slot 52 ismoved to this position blast pattern 104 is also shifted to the right asshown in FIG. 4.

Servo-unit 90 can be operated to adjust blast pattern 104 to any desiredfixed position. Alternatively, the operator can permit piston rod 82 tocontinue to reciprocate between its extreme posit-ions so that feed slot52 is rotated back and forth in a preset are for uniform blast coverageof workpiece 106 by blast pattern 104. The frequency of oscillation canbe controlled by servounit 90 through pump 92 while the amplitude ofoscillation can be adjusted by shifting stops 96 and/or 98.Additionally, the entire range of movement of blast pattern 104 can beshifted by moving both stops 96 and 98 to the right or to the left asdesired.

In accordance to another aspect of this invention, the blast pattern isalso controlled by adjusting the size of the feed slot 52. As shown inFIGS. 6-7, feed cage 40 is in the form of a pair of concentriccylindrical rings or sleeves 120 and 122, each of which contain slots124 and 126, respectively. Both ring 120 and ring 122 are mounted torotate together by arm 80 of the aforedescribed remote controlmechanism. However, additionally, inner ring 122 is mounted to rotateindependently of outer ring 120. This independent rotatable movement canbe accomplished by using a small actuator or power cylinder mounted onring 120. For example, piston shaft 128 extends through an opening 130in cylinder 120 is pivotally secured to cylinder 122. Piston shaft 128also reciprocates in hydraulic cylinder 122 which is mounted pivotablyon bracket 134 connected to outer cylinder 120. A servounit, such asunit 90 operates the cylinder-piston assembly 128, 132. The cylinderpiston assembly may also include manual stops and may otherwise besimilar to the cylinder-piston assembly shown in FIG. 1.

As Shown in FIGS. 67, the size of feed slot 52 is determined by thedegree of alignment of slots 124 and 126. When cylinder 122 is rotatedso that slots 124 and 126 .are completely aligned, the size of feed slot52 is at a maximum, and its size is reduced as cylinder 122 is rotatedto move slots 124 and 126 more out of alignment with each other.

Obviously, many modifications and variations of the present inventionare possible in the light of the above ter of said wheel, an impellercage on said blasting wheel disposed between said innermost ends of saidvanes, a feed slot in said impeller cage, remote controlled actuatingmeans connected to said impeller cage for adjusting the angularorientation of said feed slot, and said actuating means including acylinder and piston assembly and including an operating unit disposedremotely from said impeller cage and mounted externally on said housingfor operating the reciprocation of said piston in said cylinder andincluding remote means for visually noting the angular orientation ofsaid impeller cage.

2. The apparatus of claim 1 wherein said remote means for visuallynoting the angular orientation of said impeller cage includes an elasticelectrical resistor unit connected to said cylinder and piston assembly.

3. The apparatus of claim 2 wherein an electrical indicating guage isconnected to said resistor unit and is disposed remotely therefrom.

4. The apparatus of claim 3 wherein said impeller cage comprises a pairof concentric cylindrical rings, a slot being in each of said rings anddisposed to align with each other to create said feed slot, means formoving one of said rings with respect to the other of said rings wherebythe effective size of said feed slot may be varied in accordance withthe degree of alignment of said slots in said rings, said means formoving one of said concentric cylinders including a driving assemblyhaving a driving member and said driving member being connected to theinner most said concentric cylindrical rings, and said means for movingof said concentric rings being actuated by remote control means.

5. A centrifugal blasting apparatus comprising a housing open at oneend, a rotatable blasting wheel mounted in said housing, a plurality ofradial vanes on said blasting wheel with their innermost ends spacedfrom the center of said wheel, an impeller cage on said blasting wheeldisposed between said innermost ends of said vanes, a feed slot in saidimpeller cage, remote controlled actuating means connected to saidimpeller cage for adjusting the angular orientation of said feed slot,said impeller cage comprising a pair of concentric cylindrical rings, aslot being in each of said rings and disposed to align with each otherto create said feed slot, means for moving one of said rings withrespect to the other of said rings whereby the effective size of saidfeed slot may be varied in accordance with the degree of alignment ofsaid slots in said rings, and said means for moving one of saidconcentric rin-gs being actuated by remote control means.

6. An impeller cage for use in a rotatable blasting 'wheel comprising apair of concentric cylindrical rings, each of said rings having a slot,said slots being disposed in the path of motion of each other whereby afeed slot is created when said slots are aligned, means for moving oneof said rings with respect to the other of said rings whereby theeffective size of said feed slot may be varied in accordance with thedegree of alignment of said slots in each of said concentric rings, saidmeans for moving one of said cylindrical rings including a drivingassembly having a drive connected to the inner most of said concentriccylindrical rings, and said driving assembly including piston-cylindermeans.

References Cited UNITED STATES PATENTS 772,606 10/ 1904 Brossmann 302-372,236,962 4/ 1941 Wean et al. 519 2,240,248 4/1941 Turnbull 51-92,344,544 3/ 1944 Foster 51- 9 2,358,322 9/1944 Foster 5l--9 2,493,2151/ 1950 Barnes 519 LESTER M. SWINGLE, Primary Examiner.

1. A CENTRIFUGAL BLASTING APPARATUS COMPRISING A HOUSING OPEN AT ONEEND, A ROTATABLE BLASTING WHEEL MOUNTED IN SAID HOUSING, A PLURALITY OFRADIAL VANES ON SAID BLASTING WHEEL WITH THEIR INNERMOST ENDS SPACEDFROM THE CENTER OF SAID WHEEL, AN IMPELLER CAGE ON SAID BLASTING WHEELDISPOSED BETWEEN SAID INNERMOST ENDS OF SAID VANES, A FEED SLOT IN SAIDIMPELLER CAGE, REMOTE CONTROLLED ACTUATING MEANS CONNECTED TO SAIDIMPELLER CAGE FOR ADJUSTING THE ANGULAR ORIENTATION OF SAID FEET SLOT,AND SAID ACTUATING MEANS INCLUDING A CYLINDER AND PISTON ASSMBLY ANDINCLUDING AN OPERATING UNIT DISPOSED REMOTELY FROM SAID IMPELLER CAGEAND MOUNTED EXTERNALLY ON SAID HOUSING FOR OPERATING THE RECIPROCATIONOF SAID PISTON IN SAID CYLINDER AND INCLUDING REMOTE MEANS FOR VISUALLYNOTING THE ANGULAR ORIENTATION OF SAID IMPELLER CAGE.